seedling care/watering

question now is, how much do i water?? lighting is 440w VHO 48" florescent lights (4 bulbs @ 110w/ea). seedlings are about 12" from the lights, not too much heat at all -feel a slight draft with my hand under the lights (there are 2 exhaust fans - one just for lights which vents into the box and another which vents the whole enclosure through ductwork out to a window. check previous post for more details).

with the lights on temp is maintained around 85, w/ low humidity (30-40%). the jiffy cubes seem to dry out (partially, not completely) from a watering rather quickly. i dont want to drown the little seedlings but also want to make sure they have enough water to grow nicely. i originally watered them using a mister i picked up but i have a feeling that the water doesnt penetrate deep enough with it, so i pour from the mister bottle instead now.

the jiffy cubes seem to soak up everything you give it, i'm afraid to keep pouring water on it until it starts coming out the bottom - i think it will be too much. any suggestions?